The history of slavery is a subject of great interest to contemporary historians. The intense interest it evokes today is partly a consequence of one huge reality: slavery has been a feature of almost every historical epoch except for the last 200 years. So the big question is, Why and how did an institution so universal and accepted come to disappear from almost the entire world in less than a hundred years?

For many years the answer went roughly as follows: Slavery and the slave trade were accepted features of life until in the later eighteenth century a movement arose for its abolition, initially in Britain, led by figures such as William Wilberforce and Thomas Clarkson. Motivated by humanitarian concerns, the movement spread from Britain to other countries and gained a series of victories, culminating in the abolition of the slave trade in the British Empire in 1807, the abolition of slavery in the British West Indies in 1832, and the eventual extinction of slavery in the New World by 1882.

This view of abolitionism, as a humanitarian movement motivated by high ideals, was sharply criticized in a path-breaking work written in 1944. This was Capitalism and Slavery, by Eric Williams (who later became prime minister of Trinidad). Williams argued that the abolition of slavery owed little to humanitarian motives. It was rather a consequence of the appearance of modern capitalism, which had made the slave system unprofitable. It was self-interest and not humanitarian feelings that led people to abandon an age-old system. (He also argued that the earlier profits of the slave trade and the institutions it had created played a major part in Britain’s industrial revolution; but that is a separate issue, which does not concern us here.) This view became predominant for some time, not least because it appealed to people from both ends of the traditional political spectrum, although for different reasons. Supporters of capitalism argued that this showed how it was incompatible with slavery because of simple self-interest. Capitalism’s critics could use it to show how claims for human rights and liberty were merely camouflage for selfish class interests.

Williams’s work was good history in terms of its method. It rested on empirical evidence and made a number of specific claims, all of which could be tested by further research. Unfortunately for Williams, later work by many historians has undermined his thesis to the point where it is not sustainable. There had always been some serious difficulties. One was the persistence and strength of slavery in places such as Brazil and the United States. If slavery had become economically unviable because of capitalism, why had it survived so long in such a clearly capitalist economy as that of the United States?

Another difficulty was the articulation of an explicitly proslavery ideology in the American South after the 1820s, precisely when, according to Williams, the self-interest of American plantation owners should have been leading them to support abolition. This last point led supporters of Williams’s thesis into intellectual gymnastics as they sought to portray plantation owners as a “pre-capitalist” elite, despite overwhelming evidence as to their commercial-mindedness.

However, the real damage to Williams’s argument was done by the work of two historians, Roger Anstey and Seymour Drescher. They were able to demonstrate two things. First, slavery and the slave trade had been at their most profitable and their economic importance for the British economy had been greatest precisely when they became controversial, after the mid-1780s. Far from slavery’s becoming less profitable and so undermining support for it as an institution, hostility had grown along with its economic viability and importance for the slave owners and traders.1

Second, they were able to show how antislavery had become a true mass movement by the later eighteenth and early nineteenth centuries, in Britain and other countries such as France. Drescher in particular showed how abolitionism was an important part of popular culture in Britain at that time, commanding support from people who had no economic interest in the matter one way or the other.

Common Basis

More recent study suggests that there was a connection between abolitionism and capitalism, but that this connection derived from a common intellectual basis, rather than economic self-interest. Antislavery arguments drew on ideas about the common nature of all human beings, their shared natural rights to freedom, and the immorality of unfree labor (as opposed to its inefficiency). These arguments lay behind the advocacy of both abolitionism and free-market capitalism. They found expression in forms such as the famous Wedgwood medallion, which showed a kneeling chained slave, with the slogan “Am I not a man and a brother?” Another common element was the important part played by religion, particularly evangelical Protestantism and Quakerism.2

All this has important implications for our own times and the way we view current politics. The discipline of Public Choice, or the economic analysis of politics, has enormously strengthened our understanding of the way politics works. However it can also lead to despair about the prospects of ever changing anything and a consequent paralysis of the will. From a Public Choice perspective, the power of rent-seeking special interests can seem so great that any attempt to overthrow the policies they generate is ultimately futile. This can produce political quietism and apathy. What we know about abolitionism suggests that this is premature.

In late eighteenth-century Europe, slave owners and traders were a relatively small, cohesive, and easily organized group. They had a strong economic interest in the continuation and extension of both colonial slavery and the slave trade. As we now know, this interest was becoming greater rather than less after 1776, with the opening up of trade in the Americas. From a simple Public Choice perspective this should have made the abolition of, first, the slave trade and, then, slavery almost impossible. Given the concentrated benefits from slavery accruing to a relatively small group, and its access to the political system, any move to abolish the institution should have been blocked.

And yet this was not what happened. Instead, abolitionists created a true mass movement. This proved effective and ultimately successful, because it was able to win the battle of ideas and fundamentally shift the terms of argument in favor of universal human liberty.